Automatic circuit-breaker.



R. E. HELLMUND.

AUTOMATIC CIRCUIT BREAKER.

APPLIOATION FILED JAN.16, 1905.

1,123,288. Patented Jan. 5, 1915.

2 SHEETS-SHEET 1.

Fig.2-

WITNESSES.

R. E. HELLMUND.

AUTOMATIC GIRGUIT BREAKER.

APPLICATION FILED JAN. 16, 1905.

1,123,288. Patented Jan. 5, 1915.

2 SHEETS-SHEET 2.

nmunu WITNESSES: INVENTOR UNITED strAr nsfATENT OFFICE.

RUDOLF E. IIELLMUND, OF HINSDALE, ILLINOIS, ASSIGNOR, BY 'MESNE ASSIGN-MENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF EASTPITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

AUTOMATIC CIRCUIT-BREAKER Application filed January 16, 1905.

.To all whom it may concern:

Be it known that I, RUDoLF E. HELL- MUND, residing at Hinsdale, in thecounty of Dupage and State of Illinois, have invented certain new anduseful Improvements in Automatic Circuit-Breakers, of which thefollowing is a specification.

My invention refers to the construction of apparatus which are operatedor released by electromagnets and more particularly to that class ofapparatus, which are known under the name of automatic circuitbreakers.

The object of my invention is to provide a simple apparatus of thiskind, which will operate tardily upon certain conditions of electricalcurrent, and instantly upon different conditions of current in theoperating circuit. These diiferences may be classed in a great manydivisions, for instance: 1. An automatic circuit-breaker tardilyoperated on an excessive overload and rapidly operated on a greateroverload. 2. An automatic circuit breaker tardily operated on a certainunderload and rapidly operated on an underload of less value. 3. Anautomatic circuitbreaker tardily operated on a certain underload andrapidly operated upon a certain amount of reversed current.

In the specification following I have described a circuitbreaker tofulfil the'condition first enumerated. It will be obvious to one skilledin the art, that the second, third and any other condition may befulfilled in a similar way.

A further object of my invention is to provide an apparatus of the kinddescribed above with simple means to bring all parts of the apparatusback to a certain. zero position, if the conditions of current, forwhich the apparatus is tardily operated discon tinue before theoperation of the apparatus is completed.

A third object; of my invention is to pro vide an apparatus of the kindwith a form of electromagnet, which is especially adapted for thepurpose; and afourth object of my invention are novelties inconstruction as fully described and claimed in the followin claims andspecification.

%he herein described releasing device may Specification ofLetterscPatent.

Patented Jan. 5, 1915.

Serial No. 241,253.

excessive as to immediately jeopardize the installation thecircuit-breaker will be released in a tardy manner, so as to give thecondition causing the overload a chance to.

be removed before the circuit is broken,

Most of the circuit-breakers now in use are opento the serious objectionthat they operate on an excessive overloadand on an overload barelyabove that for which they are set, without distinction. If the overloadbe such as to produce a magnetic field of a little greater strength thanthe retarding force of the springor weight which prevents the operationof the circuit-breaker, the circuit is just as emphatically broken as itwould be, if an excessive and very dangerous overload were to takeplace. Several constructions, which are designed to prevent this lastobjection are too complicated in their operation, since several coilsand circuits are required for their operation. Some of theseconstructions are also objectionable, because they operate under anycondition in conjunction with a damping device and although the actionof the same is regulated for different conditions, it never allows arapid operation of the device in case of necessity. Again otherconstructions are not satisfactory, because the magnetic armature will,if advanced by a slight overload of short duration, remain in itsadvanced position and another slight overload of short duration, whichoccurs some time later will advance the armature farther and cause thedevice to operate, while this is not desirable.

The apparatus of my invention, while in no wise preventing the immediatebreaking of the circuit upon a very dangerously excessive overload,permits a slight overload such as it would be unwise to maintainconstantly to exist for an interval of time without causing-aninterruption ofthe current flow; it also permits slight overloads toexist repeatedly, if they do not occur within a too short time intervalafter each other such as to be dangerous for the circuit.

In the accompanying drawings I have illustrated several devices, bywhich this result is obtained according to my invention.

Figure 1. is a side elevation, partly in section of my referred form ofapparatus; Fig. 2. is a fi ont view thereof; Fig. 3. is a. diagrammaticview of a modified form; Fig. 4.. is a diagrammatic view of a stillfurther modified form; Fig. 5. is a side view of enough of acircuit-breaker to illustrate av form having two armatures; Fig. 6. isa. front view of Fig. 5. Fig. 7. is a side view illustration of theimproved electro-magnet by the use of whichthe action of my device isconsiderably improved; Fig. 8. is a diagrammatic view of a modificationof the same. r

The object of my invention as herein set forth, I accomplish byproviding for the movable armature, which is to release thecircuit-breaking switch, two means of retarding the motion of thearmature. These means have different forces of retardation; one of them,the lesser, acts inconjunction with a damper, and hence is caused whenmoved, to be slowly but progressively advanced. The element ofretardation, which acts in conjunction with the damper may be forinstance a weight or a spring. The other element with the greater forceof retardation comprises'a weight or a spring with a retarding force ofsuch a magnitude that 1t is not affected unless the current passingthrough the device is exceedingly dangerous, in which case the armaturewill be strongly actuated, the spring extended or the weight movedirrespective of all damping influences, and the circuit will beimmediately broken.

One or both of the retarding elements are provided and arranged so thatthe retardation shall increase as the armature moves progressivelyforward, a motion which will generally be attended by a greatlyaccelerated magnetic pull. This feature is most essential to move thearmature from any advanced position backward to its zero position, if asmall overload ceases, before the releasing member has advanced farenough to release thedevice.

In Figs. 1 and 2, I have shown an automatic circuit breaker comprising amagnet M, a rotary armature A of S-shape, loosely mounted on ashaft a,on which shaft a. weight W is keyed, while between the armature andshaft a a spring E is secured, of greater retardation than the weight W.A lever arm L on the armature serves to trip the end 2 of the pivotedlever 3, which is adapted to, release the contact blade B, so that thespring 4 may throw the blade out of contact with the clip 5. A dashpotC, a piston p and piston rod P serve as a damper such that the noses nof the armature shall always occupy a position nearer to the poles 6; 7than any other portions of the arma tures face. The operation of thisdevice on slight overload is to rotate the armature A, spring E andshaft (1 as one element, the weight W being raised on'its radial arm,its moment increasing as it approaches the horizontal, thus increasingthe retardation of the weight asthe armature rotates. A perfectlyconcentric armature face would cause acceleration of the magnetic pull,as the armature more closely approaches the field. To counteract thistendency toward magnetic acceleration and as an aid to the increasingmoment of the weight, I form the armature as shown, so that it willoccupy a position indicated on Fig. 7; when it has received its maximummotion. This motion results in producing an air gap gradually.increasing in dimension toward the rear side of the armature ole,inserting an increased magnetic resistance there to counteract theeffect of the increased amount of armature iron placed in the directionof the lines of the force of the field. A momentary increase of current,which would be great enough to lift the weight WV, but not great enoughto operate the spring E remarkably, would not cause release of the bladeB since the weight cannot move quickly, its motion being checked by thedashpot C. A continued existence of such a small increase of current,however, will cause a slow and progressive movement of the armature to aposition where the lever L strikes lever 3 and will release the blade Band break the circuit. In contradistinction to this an excessive in-vThe armature is connected by a strong spring E with a. lever B having aweight W hung in its dashpot C. On excessive overload the spring isextended very much and the armature operates the releasing deviceimmediately; on slight overload the spring is extended only a smallamount and the weight W and the dashpot are caused to retard thearmature for the rest of its Way. In this simple device, in which thespring E is the only retarding element with an increasing force ofretardation the action of same is easily understood. It is obvious thatthe spring will be always so much extended that its coefiicient oftension is equal to the magnetic pull. It, is therefore indifferent inwhich position the armature happens to be when an overload ceases; inany case the retarding force of the spring will be greater than themagnetic pull at the moment when the same decreases. Thus the springwill be able to move the armature backward.

In Fig. 4; a solenoid M is shown; a core armature A of material weightis connected by a strong spring E with a weight W in the dash-pot C arod L is adapted to tripthe releasing catch lever 31. The operation isvery similar to that of the device of Fig. 3; the only difference being,that the acceleration of the magnetic pull is retarded by graduallyincreasing the lower air gap while the resistance of the upper air gapdecreases. In order to accomplish this purpose, the lower end of thearmature A is formed comically and therefore the average distancebetween the lower end of the core and the lower end plate of thestationary iron parts of the cylindrical magnet will increase as thearmature moves upwardly. On light overload the core A the spring 1i andthe weight IV will move slowly under the retarding influence of thedash-pot and the switch will be released only if the overload continuesfor a long time. In case of a. heavy overload, however, the spring E"will be extended and the switch will be released immediately on accountof the quick upward motion of the core.

In Figs. 5 and 6, I have shown two 5- shaped armatures, each carryingindependent weights of different sizes, the weight W retarding thearmature A in conjunction with the damper D while the greater weight Eis secured to the armature A. These two armatures are provided withtripping levers L and L, respectively. On slight overload the armature Awith the larger retarding weight I] is not affected perceptibly, but thearmature A is rotated. If the overload is of long enough duration, thetripping lever L will open the switch in the manner hereinbeforedescribed. If the overload is so excessive as to be immediatelydangerous, the armature A and weight IE will be instantly rotated tooperate the tripping lever L to cause it to break the circuit in themanner hereinbefore described.

In Fig. 8, I have shown how eccentric pole faces and a concentricarmature might be used. This is an obvious reversal of the constructionshown in Figs. 1, 2, 5, 6 and 7.

In the specification herein set forth, and in the following claims, Ihave especially referred to apparatus which are controlled by certainconditions of electrical current. It is obvious to one skilled in theart. however, that apparatus which are controlled by certain conditionsof electrical potentials may be worked on the same principles and thatthey are at same time covered in the following claims in so far as anychange of a potential at the operating coils also causes a change ofcurrent in the operating coils.

\Vhat I claim as my invention 1s:

1. An automatic circuit breaker having a magnet, an armature, a weight,a dash-pot and a spring adapted to retard the motion of said armature,said spring being interposed between the weight and the armature.

2. In an automatic circuit-breaker, the combination with a latch and atripping device, of two mechanically connected but relatively movablerestraining members for said tripping device, and a damping deviceoperatively connected to one of said restraining members.

In an automatic circuit-breaker, the combination with a latch and atripping device, of two mechanically connected but relatively movablerestraining members for said tripping device that act jointly to permita slow progressive movement of the tripping device and one of which actsindependently to permit a rapid movement thereof.

4:. In an automatic circuit-breaker, the combination with a latch and atripping device, of two mechanically connected but relatively movablemembers adapted to retard said tripping device, said members beingadapted for joint slow progressive movement and one of them beingadapted for rapid independent movement and for changing its force ofretardation as the tripping device changes its position.

5. The combination with a spring-actuated but normally locked device,and a magnet, of an armature for said magnet having a tripping device,two operatively connected but relatively movable restraining members forsaid armature which oppose the pull of the magnet.

6. The combination with the tripping device of an automaticcircuit-breaker, and an electro-magnet designed to move the trippingdevice, of two mechanically connected means of different characteristicsfor opposing the movement of said tripping device, and a damper actingin conjunction with one of said opposing means 7. The combination with anormally locked device, and a spring for operating the same, of amagnetizable member, a single magnetizing coil for said member, twoconnected members adapted to retard the movement of the magnetizablemember under certain conditions of current in said coil and one of saidconnected members being adapted to permit a rapid movement of saidmagnetizable member under different conditions of current in said coil.

8. In an automatic circuit-breaker, the combination with a latch and atripping device, of a rotatively movable armature for actuating saidtripping device, and two connected means adapted to retard the rotationof the armature and to permit a slow progressive movement and one ofthem being adapted to permit a rapid movement.

9. An automatic circuit-breaker, having a magnet, an armature, a weight,a damper and a spring adapted to retard the motion of said armature,said spring being interposed between the weight and the armature.

10. An automatic circuit-breaker, having a magnet, a rotatively movablearmature, a shaft on which said armature is loosely mounted, a springbetween the armature and its shaft, a weight rigidly connected to theshaft and a damper for said weight.

11. In an automatic circuit-breaker, the combination with a latch, atripping device, a magnet and an armature, of two mechanically connectedmeans for constantly opposing the movement of the armature, and a damperfor retarding the movement of one of said mechanically connectedopposing means,

12. A rotatively movable armature for an automatic circuit-breaker, anda magnet therefor, in combination with two connected devices forretarding the movement of the armature, one device comprising a weightand a damper, and the other being a spring interposed between saidarmature and said weight.

13. A rotatively movable armature for an automatic circuit-breaker, anda magnet therefor, in combination with a shaft for the armature that mayturn independently thereof, a spring interposed between the shaft' andthe armature, a weight rigidly connected to the shaft, and a damperadapted to operate in conjunction with the weight. v

14. In an automatic circuit-breaker, an armature under the influenceiofelectrical current, two mechanically connected members designed to exerta retarding force upon said armature in the same direction to cause aslow progressive movement thereof and one of said members being adaptedto permit a rapid movement of the same, and retarding means designed towork in conjunction with one of the said members.

15. The combination with a normally locked device, and a trippingdevice, of two mechanically connected restraining members designed tooppose the operating movement of the tripping device, and a dampingdevice, said restraining members working in conjunction with the dampingdevice and being adapted for slow progressive movement of the trippingdevice and one of the restraining members acting independently of anydamping influence.

16. An automatic circuit-breaker having a magnet, a pivotally mountedarmature, a Weight, a dash-pot and a spring adapted to retard the motionof said armature, said spring being interposed between the weight andthe armature.

17 A rotatively movable armature for an automatic circuit-breaker, and amagnet therefor, in combination with a shaft for the armature that mayturn independently thereof, a resilient member interposed between theshaft and the armature, a Weight rigidly connected to the shaft, and adamper adapted to operate in conjunction with the weight.

In testimony whereof I have signed this specification in the presence oftwo subscribing Witnesses.

RUIDOLF E. HELLMUND.

Witnesses:

JULIUS JAEGER, HERMAN Wins.

